The need for a modular barrier system or retaining wall arises in many different situations and under various conditions. Common applications for such barrier systems include flood control situations, impact barriers for dangerous points on roads or highways and fortification barriers for military purposes. In many of these situations, time is of the essence and the barrier must be constructed of portable, modular components so that the barrier can be completed as quickly as possible. With flooding in particular, a retaining wall or barrier must be erected quickly in advance of rapidly rising flood waters. In these situations, the portability of the retaining wall components and the ease and speed with which the wall can be constructed are very critical features of the barrier system.
The most common type of modular barrier system known in the prior art uses standard sandbags for its component building blocks. The common sandbag includes a simple bag structure that is most often made from burlap or other similar fabric. The bag is filled through its open end with a fine aggregate material such as sand, and is closed by tying, or otherwise binding, a short length of excess fabric at this open end.
Although this basic sandbag design has proved useful for general applications, it has several shortcomings that reduce its effectiveness in many applications. For example, when common sandbags are stacked to form a retaining wall, only gravity, and to some extent the support of adjacent bags in the longitudinal direction of the wall, keeps the bags in position. In other words, the modular component bags have no positive retaining means to provide support to the wall. It follows that the common sandbag retaining wall often requires substantial depth to provide the necessary structural strength.
Another drawback of the common sandbag is that it is very difficult to lift and carry. To move one of these bags, one must stoop down and reach under the bag to lift it by its body. As these bags can weigh 100 pounds and even more when wet, and are also slippery when wet, this difficult method of picking up and carrying the bags often results in back injuries. Furthermore, these conditions prevent weaker persons from helping to move the bags at all. It is also very difficult for two small or weaker people to carry a single bag, as they must also lift the bag without a way to obtain a secure grasp of the bag. It follows that these limitations can seriously hinder efforts to quickly build a retaining wall.
In an attempt to design around the inherent instability of common sandbag walls, several designs of interlocking, semi-solid construction blocks have been made. Typical of these designs are the U.S. Pat. Nos. 3,665,669 and 3,702,520 to Huber. These patents disclose building blocks that are folded from a flat sheet of material to form a container that is filled with sand. The blocks include tabs that extend from one face and mating slots in an opposing face for receiving the tabs from an adjacent block.
Although these tabs provide a positive connection means for adjacent blocks in the wall, they also suffer from several limitations. First, the tabs are easily bent or torn off and the blocks must be handled carefully to avoid such damage. Also, building a wall with these blocks requires precisely aligning each tab with the mating slots of the adjacent block. These constraints make these blocks ill-suited for situations in which a retaining wall must be built as quickly as possible. Further, the flat sheet faces of these blocks do not provide a stable base when used on uneven ground, which is common in many retaining wall applications. Finally, the relative high cost of the containers, especially given the limited size which increases the number required per unit wall length, is a decidedly limiting factor in use.
Thus, as demonstrated by the deficiencies of the prior art, there is a need identified for a modular barrier system that provides enhanced structural integrity and stability through interconnected components, and utilizes individual bags that are highly portable and can be combined quickly and easily to form a retaining wall.